title: Copper-free click conjugation of methotrexate to a PAMAM dendrimer platform.
abstract: The synthesis of a generation 5 (G5) poly(amidoamine) (PAMAM) dendrimer platform having cyclooctyne ligands that were subsequently be used for a copper-free Huisgen 1,3-dipolar cycloaddition (click reaction) with azido modified methotrexate is described. The G5 PAMAM dendrimer was first partially (70%) acetylated and then coupled with 20 cyclooctyne ligands through amide bonds. The remaining primary amine groups on the dendrimer surface were neutralized by acetylation. The platform was then "clicked" with different numbers (5, 10, and 17) of γ-azido functionalized methotrexate. The copper-free click reactions were stoichiometric with excellent yields.
authors.affiliation: Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Baohua
authors.initials: B
authors.lastname: Huang
authors.forename: Ankur
authors.initials: A
authors.lastname: Desai
authors.forename: Hong
authors.initials: H
authors.lastname: Zong
authors.forename: Shengzhuang
authors.initials: S
authors.lastname: Tang
authors.forename: Pascale
authors.initials: P
authors.lastname: Leroueil
authors.forename: James R
authors.initials: JR
authors.lastname: Baker